Asymmetrical light-reflecting screens

ABSTRACT

An asymmetrical light-reflecting screen for tubular fluorescent lamps has wall members parallel with the longitudinal axis of the fluorescent lamp and wall members perpendicular to the said axis, and all wall members are inclined to assumed vertical planes therethrough to reflect the light rays emanating from the fluorescent lamp only in one sense in each direction longitudinally and transversely of the fluorescent lamp.

United States Patent inventor Sune Johansson Varnamo, Sweden Appl. No.713,471 Filed Mar. I5, 1968 Patented June I, 1971 Assignee ElektrisknAlrtiebolaget Enktor Vnrnarno, Sweden Priority Mar. 29, 1967 Sweden4246/67 ASYMMETRICAL LIGHT-REFLECTING SCREENS 6 Claims, 3 Drawing Figs.

US. Cl. 240/78,

240/41 .1, 240/4l.36, 240/46.39, 240/92 Int. Cl F21s 1/06 Field ofSearch 240/78, 78

(LD), 78 (LD7),4l.36,4l.l,92, 46.39, 51.11

[56] References Cited UNITED STATES PATENTS 2,837,632 6/1958 Lipscomb240/78(LD7) 2,97l,083 2/1961 Phillips 240/78(LD7) 3,169,710 2/1965Lipscomb... 240/78 3,390,263 6/ l 968 Lipscomb 240/78 PrimaryExaminer-Samuel S. Matthews Assistant Examiner-Monroe H. HayesAttorney-Karl W. Flocks PATENTEDJUN Hem 3.582.642

' SHEET 2 [1F 2 This invention relates to a light-reflecting screenhaving light directing surfaces, which is intended for tubularfluorescent lamps and which comprises light-reflecting wall meansextending in parallel with the longitudinal axis of the fluorescentlamp, and light-reflecting wall means extending perpendicularly to thesaid axis. Characteristic of the invention is that both the wall meansparallel with the longitudinal axis of the tubular fluorescent lamp andthe wall means perpendicular to said axis are inclined to the assumedvertical planes of the wall means. The invention thus provides anasymmetrical light-reflecting screen by which the light rays emanatingfrom the fluorescent lamp are directed in a definite sense, resulting inan ideal work illumination with the incident light rays fallingobliquely from behind and from the left with respect to the viewingdirection during work.

The invention will be more fully described in the following withreference to the accompanying drawings which illustrate an embodiment,chosen by way of example, of the asymmetrical light-reflecting screen.ln the drawings:

FIG. 1 is a plan view of part of the screen;

FIG. 2 is a longitudinal section of the screen combined with a tubularfluorescent lamp;

FIG. 3 is a cross section ofthe screen combined with a tubularfluorescent lamp;

FIGS. 4 and 5 on a larger scale are a longitudinal section and a crosssection, respectively, of the screen.

The light-reflecting screen consists of wall means 1 and 2 which aredisposed at right angles to each other and have light directing surfacesfor directing the light rays emanating from a tubular fluorescent lamp3. The light-reflecting wall means I extend in parallel with thelongitudinal axis of the fluorescent lamp 3 while the light-reflectingwall means 2 extend perpendicularly to the said axis.

In accordance with the invention, both the wall means 1 parallel withthe longitudinal axis of the tubular fluorescent lamp 3 and the wallmeans 2 perpendicular to said axis are inclined to the assumed verticalplanes of said wall means.

This means that if the lamp 3 is horizontal with the screen horizontallydisposed therebcneath, the wall means 1 and 2 are inclined from thevertical, while if the lamp 3 and screen are vertical, the wall means 1are inclined from the vertical and the wall means 2 are inclined fromthe horizontal; the third possibility is if the lamp 3 is disposedhorizontally and the screen is disposed vertically in spacedrelationship adjacent thereto, the wall means 1 are then inclined fromthe horizontal and the wall means 2 are inclined from the vertical.

The inclination of the wall means 1 and 2, which form the generallyplanar gridlike screen by intersecting one another, is quite apparent ineach of the figures and may be defined in relation to the plane of thescreen. Thus, when it is stated that the wall means 1 and 2 are inclinedto the assumed vertical plane of said wall means, what is meant is thatthese walls are not truly perpendicular to the plane of the screen(e.g., see FIGS. 2-5) but are inclined at an angle from theperpendicular to the plane of the screen.

In the preferred embodiment illustrated in the drawings alllight-reflecting wall means 1 are inclined in the same direction fromthe assumed vertical planes of the wall means, while alllight-reflecting wall means 2 are inclined in the same direction fromthe assumed vertical planes of said wall means. As a result, the wallmeans 1 and 2 will reflect the light rays emanating from the fluorescentlamp 3 only in one sense in each direction with respect to thelongitudinal axis and the transverse direction of the fluorescent lamp3.

The light-reflecting wall means 1 and 2 make preferably the same anglewith the assumed vertical planes of said wall means. This angle canamount to say 40. As will best be seen from FIGS. 4 and 5 which are acorrect scale reproduction of the light-reflecting screen, the wallmeans 1 and 2 are of upwardly increasing thickness, and the surface 4which is facing upwardly by reason of the inclination makes an angle of35 with the assumed vertical planes of the wall means while thedownwardly facing surface 5 makes an angle of 45 with the assumedvertical planes or the assumed horizontal plane of the wall means.

In addition to the surfaces 4 and 5, the wall means 1 and 2 also includesurfaces 6 and 7 which are located at the upper edges of the wall means1 and 2. Of these surfaces 6 and 7, surface 6 is inclined at an angle of10 and surface 7 at an angle of 36 to the assumed vertical planes ofsaid surfaces.

The light-reflecting wall means 1 and 2 are so arranged in relation toeach other as to reflect the light rays from the fluorescent lamp 3substantially in angles ranging between 60 and 15 to the vertical. Tothis end, the wall means 1 are spaced a distance of 20 mm. Also the wallmeans 2 are spaced at distance of 20 mm. The height of the screen is l8mm., the surfaces 4 and 5 amounting to 13.5 mm. of this height. At thelower ends the wall means 1 and 2 have a thickness of say 1 mm., and inthe transition between the surfaces 4, 5 and 6, 7 they have a thicknessofS mm.

In order that the light-reflecting screen shall effectively direct thelight rays in the desired directions obliquely downwardly and forwardlythe surfaces of the screen are coated with a light-reflecting layer.This layer may preferably consist ofaluminum, e.g. pure aluminum.

As will be seen from FIGS. 4 and 5 the edge portions of the screen areof such a configuration that several screens can be interconnectedwithout affecting the direction of the light rays.

The invention is not restricted to the embodiment described above andillustrated in the drawings but can be modified within the scope of theappended claims.

What I claim and desire to secure by Letters Patent is:

1. A light-reflecting, gridlike screen having light-directing surfaces,intended for tubular fluorescent lamps, comprising:

a first series of light-reflecting wall means extending parallel to thelongitudinal axis of the fluorescent lamp, and a second series oflight-reflecting wall means disposed at an angle to and intersectingwith said first series of wall means to form said gridlike screen, saidsecond series of wall means extending perpendicularly to saidlongitudinal axis of said lamp, wherein both said first and secondseries of wall means are inclined at an angle from the perpendicular tothe plane of said screen, and

wherein each of said light-reflecting wall means of said first seriesare inclined in the same direction, and wherein each of said wall meansof said second series of lightreflecting wall means is inclined in thesame direction, so that the wall means reflect the light rays emanatingfrom the fluorescent lamp only in one sense in each direction withrespect to the longitudinal axis and the transverse direction of thefluorescent lamp.

2. A light-reflecting screen as set forth in claim 1 wherein the angleof inclination from the perpendicular to the plane of said screen ofsaid wall means of said first series and said second series is the same.

3. A light-reflecting screen in accordance with claim 2 wherein saidangle of inclination is about 40 from the perpendicular to the plane ofsaid screen.

4. A light-reflecting screen in accordance with claim 3 in which thewall means are of upwardly increasing thickness, and the surface whichis facing upwardly by reason of said inclination, makes an angle ofabout 35 from the perpendicular to the plane of said screen, while thedownwardly facing surface makes an angle of about 45 from theperpendicular to the plane of said screen.

5. A light-reflecting screen as claimed in claim 1, in which the wallmeans are so arranged in relation to each other as to reflect light raysfrom the fluorescent lamp substantially at angles ranging between 60 and15 to the vertical.

6. A light-reflecting screen as claimed in claims 5, in which thesurfaces of the screen are coated with a light-reflecting layer,preferably of aluminum.

1. A light-reflecting, gridlike screen having light-directing surfaces,intended for tubular fluorescent lamps, comprising: a first series oflight-reflecting wall means extending parallel to the longitudinal axisof the fluorescent lamp, and a second series of light-reflecting wallmeans disposed at an angle to and intersecting with said first series ofwall means to form said gridlike screen, said second series of wallmeans extending perpendicularly to said longitudinal axis of said lamp,wherein both said first and second series of wall means are inclined atan angle from the perpendicular to the plane of said screen, and whereineach of said light-reflecting wall means of said first series areinclined in the same direction, and wherein each of said wall means ofsaid second series of light-reflecting wall means is inclined in thesame direction, so that the wall means reflect the light rays emanatingfrom the fluorescent lamp only in one sense in each direction withrespect to the longitudinal axis and the transverse direction of thefluorescent lamp.
 2. A light-reflecting screen as set forth in claim 1wherein the angle of inclination from the perpendicular to the plane ofsaid screen of said wall means of said first series and said secondseries is the same.
 3. A light-reflecting screen in accordance withclaim 2 wherein said angle of inclination is about 40* from theperpendicular to the plane of said screen.
 4. A light-reflecting screenin accordance with claim 3 in which the wall means are of upwardlyincreasing thickness, and the surface which is facing upwardly by reasonof said inclination, makes an angle of about 35* from the perpendicularto the plane of said screen, while the downwardly facing surface makesan angle of about 45* from the perpendicular to the plane of saidscreen.
 5. A light-reflecting screen as claimed in claim 1, in which thewall means are so arranged in relation to each other as to reflect lightrays from the fluorescent lamp substantially at angles ranging between60* and 15* to the vertical.
 6. A light-reflecting screen as claimed inclaims 5, in which the surfaces of the screen are coated with alight-reflecting layer, preferably of aluminum.